The goal of this project is to study and validate the tolerability of vaginally-administered PT-101, a novel low dose formulation of Tamoxifen Citrate for vaginal administration. PT-101 was designed to treat vulvovaginal atrophy (VVA), a condition associated with aging, menopause and breast cancer treatment. Estrogen loss is the primary cause of VVA, a condition that results in itching, burning, odor, bleeding, pain (especially with intercourse) and increased susceptibility to bacterial infections. These symptoms occur with menopause and get worse with age. The patient population includes 600,000 menopausal aged women in the United States currently using aromatase inhibitors (AI therapy) to prevent breast cancer recurrence. These patients suffer severe VVA and many often cite VVA as a reason for discontinuing their adjuvant breast cancer treatment, consequently increasing their likelihood of breast cancer recurrence when compared to those women that complete the standard five years of AI therapy. The goal of AI therapy is to lower systemic estrogen levels to prevent a breast cancer recurrence. Women taking aromatase inhibitors are contraindicated for using the only effective treatment for VVA - estrogen therapy. Even local estrogens have been demonstrated to have significant systemic uptake. Moreover, many menopausal age women without breast cancer do not use estrogen therapy due to real and perceived serious risks associated with chronic estrogen use. Pear Tree Pharmaceuticals has developed PT-101 to treat VVA without the dangerous side-effects associated with hormone-based therapies. The proposed project will enable Pear Tree to compete in vivo studies to determine safety and tolerability of this novel product candidate. Following a successful study, Pear Tree intends to file a company-sponsored Investigational New Drug Application [IND] so that it can evaluate the safety and efficacy of PT-101 in patients suffering VVA, including those menopausal age women undergoing AI Therapy. PUBLIC HEALTH RELEVANCE: This proposed project will benefit public health by enabling the development of a safe and effective treatment for the growing population of aging women suffering vulvovaginal atrophy. Menopausal age breast cancer survivors currently have no available safe and effective treatment for the condition.